Fire-box.



Pat'gnted N ov. l3, I900.

B. B. HOISINGTON.

FIRE BOX.

(Application filed may 5, 1900.)

2 Sheets-Sheet I.

(No Model.)

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' machines.

and an imperforate bottom section 7.

UNITED STATES PATENT OFFICE,

BENJAMIN R. HOISINGTON, OF MINNEAPOLIS, MINNESOTA,

FIRE- Box.

I SPECIFICATION forming part of Letters Patent No. 661,803, datedNovember 13, 1900. Application filed May 5, 1900. Serial No. 15,564- (Nomodel.)

To aZZ whom/it may concern;

Be it known that I, BENJAMIN R. HOISING- TON, a citizen of the UnitedStates, residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented certain new and useful Improvements in Fire-Boxes; and I do hereby declare the following to be a full, clear, andexact description of the invention, suohvas will enable others skilledin the art to which it appertains to make and use the same.

My present invention has for its objectto improve the construction ofboiler fire-boxes with a viewof obtaining the maximum of heating-surfaceand hence the maximum of generating efficiency.

To this end the invention consistsof the novel devices and combinationsof devices hereinafter described, and defined inf-the claims. t I i Theinvention is illustrated in the accompanying drawings, wherein'likecharacters Figure 1 is a view, partly in side elevation and partly inlongitudinal vertical section,showing a boiler having a fire-boxconstructed in accordance with my invention. Fig. 2 is a transversevertical section on the line x 00 of Fig. 1, and Fig. 3 is a horizontalsection approximately on the line m 00 of Fig. 1.

In the drawings 1 have illustrated the features of my invention asincorporated in the fire-box construction of a traction-engine such asused in connection with threshing- The numeral 1, indicates the body ofthe boiler, and the numerals 2 and 3 indicate,respectively, the frontandrear wheels of the engine, certain parts of the engine being removed.

The main or primary portion 4 of the firebox is formed between or withinwater-jacketed walls 5, and the bottom of said fire-box is shown as madeup of. an ordinary grate 6 An ordinary fire-door 8 opens and closes anordinary opening in the rear wall of the fire-box to afiord means forsupplying fuel into the primary chamber or fire-box proper, at.

The boiler fines or tubes 9 extend backward, preferably, over more thanhalf of the fire-box or primary chamber t and are secured at their endsin the ordinary manner in suitable openings of a flue-sheet 10. Awater-chamber 11, which communicates with the main body of the boiler,depends into the primary chamber 4:, but terminates at its ends short ofthe front and rear walls of the said chamber at, as best shown inFig. 1. Extending longitudinally and approximately horizontally throughthe water-chamber 11 is a combustion-passage 12, which is preferablyrectangular in cross-section and made thinner or contracted atits rearend. The rearinner wall of the fire-box 4: is extended upward and thenforward, forming a crown-sheet, as shown at 13, and is connected at itsforward edge to the upper edge of the flue sheet 10. Thus a supplementalor secondary combustion-chamber .14 is formed above the chamber at andbe tween the said chamber 4 and the fines 9.

The products of combustion for the burning fuel may pass from theprimary chamber L to the supplemental or secondary combustion-chamberlatby either one or both of two routes, to wit: the one through thecombustion-passage 12 and upward into the said chamber 14 and the otherdirectly upward from the said chamber4 through acontracted passage 15and thence into the said chamber 14:. The contracted passage 15 isadapted to be closed and opened more or less by a dam: per-plate 16,which rests upon a shelf 17, secured to the rear inner wall of thefire-box. To hold the damper-plate 16 where set, it is provided at itsends'with lugs 18, adapted to fit. between any two of a series of teethor; lugs 19 onthe ends of the shelf 17. To provide for the adjustment ofthe said damper "16 from the exterior of the tire-box, it is shown asprovided with an eye or perforated lug 2 0, with which the end of apoker or similar tool maybe engaged. To provide for the insertion of thepoker, the lire-box is provided with a small door above the shelf 17.

It will be noted that the crown-sheet 13 of the auxiliary chamber 1 1 isbelow the level of a column of water z, so that this sheet 13 servesalso as a generating-surface. It will also be noted that thecombustion-passage 12 is less in width than the combustion-chamberse and14. To give free circulation of the water from the water-jacketed sidesof the fire-box to the sides of the water-chaintaste berll, theinnerside walls of the firebox are 1 cut away opposite to the saidwater-chamber 11, as shown at 22, and water-tightjoints are formedbetween the sides of the said waterchamber 11 and the said Walls ofthe'firebox by means of riveted and calked strips 23. v

(Best shown in Fig. 3.) The horizontal crown-sheet 24 at the top of theprimary com bustion-chamber4 and at the top of the passage 12 ispreferably additionally supported from the top of the boiler by rods 25.Other rods and bolts are employed Wherever desired to give additionalstrength and rigidity to the parts.

With a fire-box constructed as above described and with the passage 15opened by the damper 16 the products of combustion or burningfuel flameswill divide, part passing through the return draft-passage 12 and fromthence into the secondary combustion-chamber 14 and partpassing underthe bottom of the Water-chamber 11 and upward through the passage l5intothe said secondary chamber 14. As .the divided products reunitein thesecondary combustion-chamber 14 the combustion will be again intensifiedby the intermiuglirig of the flames or burning gases and from thischamber will be again'divided and passed: forward through the ordinaryfiues 9. By regulating the damper '16 more;

or lessof the draft and burning products may be directedthrough thepassages 12 and 15, so. that in this'way the best distribution of heaton the generating-surfaces may be attained;

in presence of-two witnesses.

From the above description it obvious that a very large amount ofgenerating or heating surface is exposed tovthe flame; also, by

dividing the burning gases and reuniting them the combustion is renderedmore COIII- plete, which of itself results in asaving of fuel andenergy.

What I claim, and desire to secure by Let ters Patent of the UnitedStates, is as follows:

. 1. In a fire-box, the combination with a primary combustion-chamber,of a secondary combustion-chamber above the same leading to the lines, adirect passage between said combustion-chambers, and an approximatelyhorizontal water-jacketed return draft-passage leading from thesaid'primary to said secondary chamber, substantially as de- Witnesses:

i r MABEL M. MCGRORY, D. MERCHANT.

BENJAMIN R. H'OISINGTON.- l

